Beta-N-oxalylamino-L-alanine action on glutamate receptors

• Published in: Journal of neurochemistry Vol. 53; no. 3; p. 710
• Main Authors: Ross, S M, Roy, D N, Spencer, P S
• Format: Journal Article
• Language: English
• Published: England 01-09-1989
• Subjects: Alanine - analogs & derivatives; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; Amino Acids, Diamino; Animals; Aspartic Acid - analogs & derivatives; Aspartic Acid - metabolism; beta-Alanine - analogs & derivatives; beta-Alanine - pharmacology; Binding, Competitive; Brain - drug effects; Brain - metabolism; Cerebellum - metabolism; Cerebral Cortex - drug effects; Cerebral Cortex - metabolism; Corpus Striatum - metabolism; Hippocampus - metabolism; Ibotenic Acid - analogs & derivatives; Ibotenic Acid - metabolism; Kainic Acid - metabolism; Male; Mice; N-Methylaspartate; Oxadiazoles - metabolism; Piperazines - metabolism; Quisqualic Acid; Receptors, Glutamate; Receptors, Neurotransmitter - drug effects; Receptors, Neurotransmitter - metabolism; Spinal Cord - drug effects; Spinal Cord - metabolism; Synaptic Membranes - metabolism; Thiocyanates - pharmacology
• ISSN: 0022-3042
• DOI: 10.1111/j.1471-4159.1989.tb11762.x

beta-N-Oxalylamino-L-alanine (L-BOAA) is a non-protein excitatory amino acid present in the seed of Lathyrus sativus L. This excitotoxin has been characterized as the causative agent of human neurolathyrism, an upper motor neuron disease producing corticospinal dysfunction from excessive consumption of the lathyrus pea. Previous behavioral, tissue-culture, and in vitro receptor binding investigations revealed that L-BOAA might mediate acute neurotoxicity through quisqualate (QA)-preferring glutamate receptors. The present study demonstrates the stereospecific action of L-BOAA on glutamate receptor binding in whole mouse brain synaptic membranes. L-BOAA was most active in displacing thiocyanate (KSCN)-sensitive specific tritiated (RS)-alpha-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) binding (i.e., QA receptor) (Ki = 0.76 microM) with a rank-order potency of QA greater than kainate greater than N-methyl-D-aspartate (NMDA). By contrast, the nonneurotoxic D-BOAA isomer (100 microM) was essentially inactive in displacing radioligands for glutamate receptors, except the NMDA site, where it was equipotent with L-BOAA. Scatchard analysis of L-BOAA displacement of specific [3H]AMPA binding indicated competitive antagonism (KD: control, 135 nM; L-BOAA, 265 nM) without a significant change in QA-receptor density, and Hill plots yielded coefficients approaching unity. Differential L-BOAA concentration-dependent decreases in specific [3H]AMPA binding were observed in synaptic membranes, indicating that the neurotoxin was more potent in displacing specific binding from frontal cortex membranes, followed by that for corpus striatum, hippocampus, cerebellum, and spinal cord.